Telescopic counterbalance

ABSTRACT

A telescopic counterbalance for a hinged closure includes inner and outer telescopically related members. An internal compression spring biases the members apart to their telescopic outward position. The members are located in this position by the engagement of a collapsed rib located intermediate of the outer member with a plurality of spaced depressions located intermediate of the inner member. The members are releasably retained in this position by a spring clip on the outer member cooperating with the collapsed rib. The inner flared end of the inner member engages intermediately of the outer member and a plastic bushing on the inner end of the outer member engages intermediately of the inner member for improved bending strength. A wooden dowel mounted internally of the outer member extends through the compression spring and supports a compression spring on the free end thereof. This is engaged by a spring seat on the inner member during the terminal inward movement of the inner member to provide a pop-open force or additional opening force upon initial telescopic outward movement of the members.

United States Patent Sandor Dec. 3, 1974 i 1 TELESCOPIC COUNTERBALANCEcludes inner and outer telescopically related members.

[75] Inventor Bela Sandor, D ctr Oit Mich. An internal compressionspring biases the members apart to their telescopic outward position.The meml Assignee: General Motors Corporation, bers are located in thisposition by the engagement of Detroit, Mich. a collapsed rib locatedintermediate of the outer mem- (221 Filed: Apr. 26 1973 her with aplurality of spaced depressions located intermediate of the innermember. The members are rel l pp 354,702 leasably retained in thisposition by a spring clip on the outer member cooperating with thecollapsed rib.

52 US. Cl. 292/262, 292/338 The imler flared end of the inner memberengages 151 Int. Cl. E05c 17/30 F l of the outer member and a Plastic[58] Field of Search 292/262, 338; 16/49, 84, mg F the Outer memberengages 16/85, 72, 197; 248/354, 402, 403; 49/379 termedrately of theinner member for improved bendmg strength. A wooden dowel mountedinternally of [56] References Cited the outerdmember extends through thecomprrlesi ion spring an supports a compresslon sprm on t e ree UNITEDSTATES PATENTS end thereof. This is engaged by a spring seat on the2.071660 2/1937 SCl'lUlZ CI 8i. X inner member during the terminalinward mo ement 11332 g 292/338 of the inner member to provide apop-open force or 5:714:67; 2/1973 s h l id iiiiiI::::::::.::::::::i:i::16/85 x additional Opening force upon initial telescopic PrimaryE.raminerRichard E. Moore Attorney, Agent, or Firml-lerbert Furman [57]ABSTRACT A telescopic counterbalance for a hinged closure inwardmovement of the members.

8 Claims, 8 Drawing Figures PATENTEE DEC 3 SIEEY 10F 2 TELESCOPICCOUNTERBALANCE This invention relates generally to telescopiccounter-balances and more particularly to a telescopic counterbalanceincluding a pop-open force which aids the counterbalance force ininitially moving the telescopic members of the counterbalance towardextended position.

Telescopic type counterbalances are known. Generally, suchcounterbalances include inner and outer telescopically related tubularmembers which are biased outwardly of each other or toward extendedposition by an internal compression spring seating on respective springseats internally of the outer ends of the members. The outer ends of themembers are respectively pivotally connected to a closure and to theclosure support to bias the closure to its open position and also tocounterbalance the closure as it moves between open and closedpositions. A stop on the inner end of the inner member is engageablewith a stop adjacent the outer end of the outer member to locate themembers in their extended position.

The counterbalance of this invention is of the telescopic type. butdiffers from known counterbalances in additionally including severalfeatures. One feature is that a booster compression spring is mounted onone of the telescopic members and is engaged and compressed by anabutment on the other member during the terminal inward movement of themembers to store energy and provide an initial pop-open force aiding themain compression spring in initially biasing the members outwardly ofeach other and consequently initially biasing the counterbalancedclosure toward a partially open position. Another feature is that thebooster compression spring is mounted on the outer member internally ofthe main compression spring and is located adjacent the inner end of theouter member. The popopen force provided by the booster spring is veryuseful and desirable in conjunction with heavy vehicle closures such ashatch backs. A further feature is that the outer member is provided witha snap ring which must be bypassed by a stop on the inner member inorder to provide a releasable detent for the members in their telescopicoutward position. Yet another feature of this invention is that theouter member includes a resilient plastic bushing at its inner end whichseats intermediately of the inner member and provides for frictionlessmovement of the members relative to each other and increases the bendingstrength of the members.

These and other features will be readily apparent from the followingspecification and drawings wherein:

FIG. I is a partial rear elevational view of the vehicle body having aclosure mounted thereon for movement between open and closed positionsand counterbalanced by a telescopic counterbalance according to thisinvention;

FIG. 2 is an enlarged partially broken away view of the telescopiccounterbalance;

FIG. 3 is an enlarged view of a portion of FIG. 2;

FIG. 4 is an enlarged sectional view taken generally along the planeindicated by line 44 of FIG. 2;

FIG. 5 is an enlarged sectional view taken generally along the planeindicated by line 55 of FIG. 2;

FIG. 6 is an enlarged view of a portion of FIG. 2;

FIG. 7 is an enlarged view of a portion of FIG. 2; and

FIG. 8 is an enlarged view of a portion of FIG. 2.

Referring now particularly to FIG. 1 of the drawings, a vehicle bodydesignated generally 10 includes a rear opening 12 which is opened andclosed by a hatch or closure 14 which is conventionally hinged to thebody adjacent the forward edge of the opening. The closure 14 iscounterbalanced during movement between an open position, as shown, anda closed position, not shown, wherein it closes opening 12, by a pair oftelescopic counterbalances 16 according to the invention. Thecounterbalances 16 are respectively pivotally connected at the outerends thereof to the closure 14 and to the body 10 and are of likeconstruction. Accordingly, only one will be described in detail and itwill be understood that the other is the same.

Referring now to FIG. 2, the counterbalance 16 includes an outer orfemale tubular member 18 and an inner or male tubular member 20. Themembers can be formed of any conventional material. A spring seat or cup22 seats within the member 18 adjacent the free or outer end thereof andis secured in place by spaced pairs of dimples 24 which engage the freeedge of the cup 22 and also engage underneath the base wall 26 thereof.The member 18 adjacent to the cup 22 is co]- lapsed upon itself andformed into a double walled cupshaped end portion 28. The material ofthe base wall of this end portion is formed to provide a circularflanged opening 30 which receives a headed plastic grommet 32. The headof the grommet engages the base wall of portion 28 and the split legs ofthe grommet extend outwardly through the opening 30 and engage under theflange thereof. A conventional headed bolt 34 is received through thegrommet and attaches the member 18 to a suitable mounting on the body10.

As shown in FIGS. 2 and 7, a spring seat or cup 36 is received in themember 20 adjacent the free or outer end thereof and is retained inplace by spaced pairs of dimples 38 engaging both the base wall and thefree edge thereof. The member 20, adjacent the cup 36, is collapsed uponitself in the same manner as member 18 and formed into a cup-shaped endportion 40. The material of the base wall of this end portion is formedin the same manner as that of end portion 28, into a flanged opening 42which receives a grommet 44 of the same construction as grommet 32.Grommet 44 receives a bolt 46 which secures the member 20 to the closure14. Thus, the free or outer ends of the members 18 and 20 arerespectively secured to the body 10 and to the closure 14 for pivotalmovement relative thereto as the members 18 and 20 move-telescopicallyrelative to each other between their telescopic outward and inwardpositions as the closure moves respectively between open and closedpositions. The double walled construction of the end portions 28 andinsures that these portions will have adequate strength under allservice conditions. The grommets 32 and 44 obviate all noise problemscaused by pivotal movement of the members 18 and 20 relative to thebolts 34 and 46. Additionally, the cups 22 and 36 function as diesduring the forming of the end portions 28 and 40.

A main coil compression spring 48 extends continuously through themembers 18 and 20. One end of the spring seats on the base wall 26 ofthe cup 22 while the other end of the spring seats on the base wall ofcup 36 to continually bias the members 18 and 20 apart or to theirtelescopic outward position relative to each other. A circular woodendowel 50 has one end thereof received and retained in a centraldepression 52 of the member 26. The dowel 50 extends through the spring48 and controls snaking of this spring relative to the members 18 and 20as the spring is compressed when the members 18 and 20 move to theirtelescopic inward position. By using a wooden dowel objectionable noisecaused by movement of the spring relative to the dowel is reduced to aminimum.

The dowel 50 includes an integral extension 53 of reduced diameter. Acoil compression spring 54 surrounds the extension 53 and extendsoutwardly therefrom for approximately half its length. The spring 54 isretained on the extension by having a coil 56 thereof of reduceddiameter received within an annular groove of the extension.

As best shown in FIGS. 2, 3, and 5, the member 18 is provided with threeequally spaced rectangular shaped depressions 58 of arcuate crosssection. The depressions are formed intermediately of member 18 and areformed by pressing in portions of the wall of this member. The member 20is provided with an intermediate integral collapsed rib 60 which isengageable with the innermost end walls 61 of the depressions, FIG. 3,when the members are in their telescopically extended position toprovide a primary fixed stop limiting telescopic outward movement of themembers. Additionally, as shown in FIG. 2, the inner end of member 20 isprovided with a flared or cup-shaped terminal portion 62 which isslidable within the member 18 and is of an outer diameter slightly lessthan the inner diameter of the member. As shown in FIGS. 2 and 6, theinner end of the member 18 is provided with an inwardly opening integralgroove 64 which receives the flange 66 of a plastic bushing 68 slidablyreceiving member 20. Bushing 68 is suitably retained as by lancedinwardly deflected tabs. As previously mentioned. the engagement of therib 60 with the end walls 61 of the depressions 58 provides a primaryfixed stop. Should this primary stop fail for any reason, the engagementof the portion 62 with the bushing 68 provides a secondary stop.Additionally, the sliding engagement of portion 62 with member 18, andthe sliding engagement of bushing 68 with member 20 provide spacedsupport points for the members 18 and 20 to increase the bendingstrength of the counterbalance in its various extended positions.

The member 18, as shown best in FIGS. 2 and 4, includes diametricallyopposite slots 70 which receive the straight legs 72 ofa generallyC-shaped clip 74 partially surrounding the member 18. The legs 72 andthe rib 60 provide a releasable detent for the members 18 and 20 intheir fully extended position since the rib must move past these legsduring both inward and outward telescopic movement of the members 18 and20.

The counterbalance 16 is shown in FIG. 2 in its extended position withthe closure 14 in its open position. Spring 48 countcrbalances theclosure in this position and engages rib 60 with the end wall 61 ofdepressions 58. As the closure 14 moves toward its closed position andthe members 18 and 20 telescope inwardly, the rib 60 initially movespast the legs 72 by forcing these legs apart relative to each other inorder to release the detent. As the members 18 and 20 continue to moveinwardly of each other, the spring 48 is compressed and counter-balancesthe weight of the closure 14. When the closure 14 is substantiallyclosed, such as within 13 of closed position, the free end of the spring54 will engage and seat a central conical seat 76, FIG. 7, of the cup 36during the final closing movement of the closure 14. In the specificembodiment shown, this engagement will occur at approximately the finall3 of closing movement of the closure 14. Further movement of theclosure 14 to its final closed position will then compress the spring 54to store spring energy. The free end of the extension 53 will beslightly spaced from the seat 76 when the closure 14 is in its closedposition. The closure will be retained in this position by aconventional releasable latch.

When such latch is released to open the closure 14, the energy stored inthe spring 54 adds to that stored in spring 48 to provide an additionalpop-open force aiding the spring 48 in quickly moving the closure to apartially open position wherein the seat 76 moves out of engagement withthe spring 54. The closure 14 is counterbalanced for the remainder ofits opening movement by the spring 48.

Thus, this invention provides an improved telescopic counterbalance.

What is claimed is:

1. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, resilient counterbalance means seatingbetween the members to bias the members in a telescopic outwarddirection and bias the closure to an open position, booster spring meansmounted on one of the members, and abutment means mounted on the othermember, the booster spring means being normally in a free position andbeing engaged and compressed by the abutment means only during finalinward telescopic movement of the members to provide a pop-open forcecooperating with the resilient counterbalance means in initially biasingthe closure to a partially open position.

2. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination. apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, main counterbalance spring means seatingbetween the members to bias the members in a telescopic outwarddirection and bias the closure to an open position, booster spring meansmounted on one of the members and located within the main spring means,and abutment means mounted on the other member, the booster spring meansbeing normally in a free position and being engaged and compressed bythe abutment means only during the terminal inward telescopic movementof the members to provide a pop-open force cooperating with the mainspring means in initially biasing the closure to a partially openposition.

3. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, main spring means within the membersseating between the outer ends of the members to bias the members in atelescopic outward direction and bias the closure to an open position,booster spring means, means mounting the booster spring means adjacentthe inner end of one olthe members, and abutment means mounted on theother member adjacent the outer end thereof, the booster spring meansbeing normally in a free position and being engaged and compressed bythe abutment means only during inward telescopic movement of the membersto provide a pop-open force cooperating with the main spring means ininitially biasing the closure to a partially open position.

4. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, spring seat means located adjacent theouter ends of the members internally thereof, main spring means seatingon the spring seat means to bias the members in a telescopic outwarddirection and bias the closure to an open position, an annular membermounted on the spring seat means of one member and extending through themain spring means to adjacent the inner end of said one member tocontrol snaking of said main spring means, booster spring means mountedon said annular member, and abutment means mounted on the other member,the booster spring means being engaged and compressed relative to saidannular member by the abutment means during final inward telescopicmovement of the members to provide a pop-open force cooperating with themain spring means in initially biasing the closure to a partially openposition.

5. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, resilient counterbalance means seatingbetween the members to bias the members in a telescopic outwarddirection and bias the closure to an open position, releasable detentmeans releasably locating the members in a telescopic outward position,booster spring means mounted on one of the members, and abutment meansmounted on the other member, the booster spring means being normally ina free position and being engaged and compressed by the abutment meansonly during final inward telescopic movement of the members to provide apop-open force cooperating with the resilient counterbalance means ininitially biasing the closure to a partially open position.

6. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, innerand outer telescopic annular members movable between extended andretracted positions relative to each other, means securing the outerends of the members respectively to the support and to the closure,resilient counterbalance means seating between the members to bias themembers to a telescopic extended position and bias the closure to anopen position, resiliently deflectable detent means mounted on the outermember, means on the inner member engageable with the detent means andmovable therebeyond to provide a releasable detent holding the membersin a telescopic extended position against movement to a telescopicretracted position,

booster spring means mounted on one of the members, abutment meansmounted on the other member, the booster spring means being engaged andcompressed by the abutment means during movement of the members to atelescopic retracted position to provide a popopen force cooperatingwith the resilient counterbalance means in initially biasing the membersto telescopic extended position and biasing the closure to a partiallyopen position, and means on the outer member engageable with the meanson the inner member upon movement of the means on the inner memberbeyond the detent means to provide a stop in the extended position ofthe annular members.

7. The combination recited in claim 5 wherein the releasable detentmeans includes spaced resiliently defiectable means on one of theannular members normally located adjacent the other annular member, andmeans on the other annular member engageable with and movable past thedeflectable means in the telescopic outward position of the annularmembers.

8. The combination recited in claim 5 wherein the releasable detentmeans includes resiliently deflectable means on one of the telescopicmembers normally lo cated adjacent the other annular member, and stopmeans on the other annular member engageable with and bypassing theresiliently deflectable means during outward movement of the annularmembers relative to each other. the one annular member including secondstop means engageable with the first stop means on the other annularmember after the first stop means has bypassed the resilientlydeflectable means to thereby provide a fixed stop limiting outwardtelescopic movement of the members.

l l l

1. A telescopic counterbalance for a closure movable between open andclosed positions relative to a support comprising, in combination, apair of telescopic annular members movable inwardly and outwardly ofeach other, means securing the outer ends of the members respectively tothe support and the closure, resilient counterbalance means seatingbetween the members to bias the members in a telescopic outwarddirection and bias the closure to an open position, booster spring meansmounted on one of the members, and abutment means mounted on the othermember, the booster spring means being normally in a free position andbeing engaged and compressed by the abutment means only during finalinward telescopic movement of the members to provide a popopen forcecooperating with the resilient counterbalance means in initially biasingthe closure to a partially open position.
 2. A telescopic counterbalancefor a closure movable between open and closed positions relative to asupport comprising, in combination, a pair of telescopic annular membersmovable inwardly and outwardly of each other, means securing the outerends of the members respectively to the support and the closure, maincounterbalance spring means seating between the members to bias themembers in a telescopic outward direction and bias the closure to anopen position, booster spring means mounted on one of the members andlocated within the main spring means, and abutment means mounted on theother member, the booster spring means being normally in a free positionand being engaged and compressed by the abutment means only during theterminal inward telescopic movement of the members to provide a pop-openforce cooperating with the main spring means in initially biasing theclosure to a partially open position.
 3. A telescopic counterbalance fora closure movable between open and closed positions relative to asupport comprising, in combination, a pair of telescopic annular membersmovable inwardly and outwardly of each other, means securing the outerends of the members respectively to the support and the closure, mainspring means within the members seating between the outer ends of themembers to bias the members in a telescopic outward direction and biasthe closure to an open position, booster spring means, means mountingthe booster spring means adjacent the inner end of one of the members,and abutment means mounted on the other member adjacent the outer endthereof, the booster spring means being normally in a free position andbeing engaged and compressed by the abutment means only during inwardtelescopic movement of the members to provide a pop-open forcecooperating with the main spring means in initially biasing the closureto a partially open position.
 4. A telescopic counterbalance for aclosure movable between open and closed positions relative to a supportcomprising, in combination, a pair of telescopic annular members movableinwardly and outwardly of each otheR, means securing the outer ends ofthe members respectively to the support and the closure, spring seatmeans located adjacent the outer ends of the members internally thereof,main spring means seating on the spring seat means to bias the membersin a telescopic outward direction and bias the closure to an openposition, an annular member mounted on the spring seat means of onemember and extending through the main spring means to adjacent the innerend of said one member to control snaking of said main spring means,booster spring means mounted on said annular member, and abutment meansmounted on the other member, the booster spring means being engaged andcompressed relative to said annular member by the abutment means duringfinal inward telescopic movement of the members to provide a pop-openforce cooperating with the main spring means in initially biasing theclosure to a partially open position.
 5. A telescopic counterbalance fora closure movable between open and closed positions relative to asupport comprising, in combination, a pair of telescopic annular membersmovable inwardly and outwardly of each other, means securing the outerends of the members respectively to the support and the closure,resilient counterbalance means seating between the members to bias themembers in a telescopic outward direction and bias the closure to anopen position, releasable detent means releasably locating the membersin a telescopic outward position, booster spring means mounted on one ofthe members, and abutment means mounted on the other member, the boosterspring means being normally in a free position and being engaged andcompressed by the abutment means only during final inward telescopicmovement of the members to provide a pop-open force cooperating with theresilient counterbalance means in initially biasing the closure to apartially open position.
 6. A telescopic counterbalance for a closuremovable between open and closed positions relative to a supportcomprising, in combination, inner and outer telescopic annular membersmovable between extended and retracted positions relative to each other,means securing the outer ends of the members respectively to the supportand to the closure, resilient counterbalance means seating between themembers to bias the members to a telescopic extended position and biasthe closure to an open position, resiliently deflectable detent meansmounted on the outer member, means on the inner member engageable withthe detent means and movable therebeyond to provide a releasable detentholding the members in a telescopic extended position against movementto a telescopic retracted position, booster spring means mounted on oneof the members, abutment means mounted on the other member, the boosterspring means being engaged and compressed by the abutment means duringmovement of the members to a telescopic retracted position to provide apop-open force cooperating with the resilient counterbalance means ininitially biasing the members to telescopic extended position andbiasing the closure to a partially open position, and means on the outermember engageable with the means on the inner member upon movement ofthe means on the inner member beyond the detent means to provide a stopin the extended position of the annular members.
 7. The combinationrecited in claim 5 wherein the releasable detent means includes spacedresiliently deflectable means on one of the annular members normallylocated adjacent the other annular member, and means on the otherannular member engageable with and movable past the deflectable means inthe telescopic outward position of the annular members.
 8. Thecombination recited in claim 5 wherein the releasable detent meansincludes resiliently deflectable means on one of the telescopic membersnormally located adjacent the other annular member, and stop means onthe other annular member engageable with and bypassing the resilientlydeflectable means during outward movement of the annular meMbersrelative to each other, the one annular member including second stopmeans engageable with the first stop means on the other annular memberafter the first stop means has bypassed the resiliently deflectablemeans to thereby provide a fixed stop limiting outward telescopicmovement of the members.